 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui;

 /**
  * Manages a list of entries to keep a history of locations on editors,
  * enabling the user to go back and forward without losing context.
  *
  * The history is a list of <code>INavigationLocation</code> and a pointer
  * to the current location. Whenever the back or forward action runs the
  * history restores the previous or next location.
  *
  * The back and/or forward actions should not change the content of the history
  * in any way.
  *
  * If the user steps N times in one direction (back or forward) and then N times to
  * the oposite direction, the editor and location should be exactly the same as before.
  *
  * Clients must guarantee that the current location is
  * always in the history, which can be done either by marking
  * a new location or by updating the current location.
  *
  * Not intended to be implemented by clients.
  *
  * @since 2.1
  */
 public interface INavigationHistory {
     /**
      * Mark the current location into the history. This message
      * should be sent by clients whenever significant changes
      * in location are detected.
      *
      * The location is obtained by calling <code>INavigationLocationProvider.createNavigationLocation</code>
      */
     public void markLocation(IEditorPart part);

     /**
      * Returns the current location.
      *
      * @return the current location
      */
     public INavigationLocation getCurrentLocation();

     /**
      * Returns all entries in the history.
      *
      * @return all entries in the history
      */
     public INavigationLocation[] getLocations();
 }

